This is good and timely advice.
I think many of us adults revert to our 11 year old selves around coaches and lose whatever problem solving skills we have developed in other areas of our adult lives.
Also we tend to be over invested in our horses emotionally so it becomes less “how do I fix this problem?” and more anxiety about how the horse reflects on us.
There is also the fine line between coach and friend. Most of the time you aren’t really friends with your coach. And if you are it isn’t necessarily a 100 % great thing as then you can be expected to take a back seat to new paying customers because you understand how hard coaches life is :).
Add children into the mix and the mom client who knows little about horses is even more likely to panic and bolt when “her child’s safety” is at risk.
Absolutely the OP should sit down and talk to trainer. Indeed we don’t know enough about the situation to even advise. But it is possible the whole setup and expectations are wrong for her.
It’s also possible that OP is acting in a way that communicates to the trainer that OP is blaming trainer for the poor results at the last show. Horse is always perfect for everyone else. Somehow I think there’s more to the story than that. Especially if trainer rode horse successfully in past.
Had trainer tried to tell OP about problems that OP doesn’t want to hear? Had OP withdrawn from trainer?
What does OP ultimately want? To show her own horse or to be an owner in the bleachers? These are things OP needs to know before she has a sit-down with coach.